Shimano Freehub Bearing Repair FH M678 DEORE SLX XT SAINT ZEE

FH-M678 repair.
0:00 The basics
00:39 Main tools needed
2:16 Freehub tool install
3:49 Undoing top of freehub
5:29 Removing freehub body from wheel hub
6:13 What the FH-M678 looks like
6:43 Freehub top disassembly
9:00 Opening the main body of the freehub
10:48 Pawl system strip
12:24 Pawl discussion
13:20 Pawl system rebuild
15:17 To grease or not to grease?
16:35 Army of ball bearings
21:13 Installing pawl system back into the Fhub body
23:35 Rebuilding the top of the freehub (Washers)
25:10 Nothing really, just some sped up footage
26:53 How the top bearings should look
27:07 Top back on
28:34 Reinstalling the freehub to the wheel hub
29:58 Tightening the freehub bearing race on the wheel
Bearings are 3/32 which is 2.38mm.
Grade 10 is recommended.
Chrome steel or stainless steel.
15mm allen key needed to remove the freehub from the wheel.
This ebay link is not affiliated with me and it's not my account.
Freehub tool - www.ebay.co.uk/itm/3040806163...
The music is free from slip.stream, they allow you to use it in YT videos without copyright strikes under certain circumstances.

[@robinrai4973]

Very nice, thanks! I used that threaded bar trick to remove my properly stuck on bottom bracket. Instead of tightening it all the way, I used two bolts on either side to give it some slack for the parts to thread out a bit.

[@yeatiful]

very professional and plenty of tips!

[@sergion1406]

Thank you very much for sharing this information with us.

[@eddievillar8798]

Thank you Sir for that Idea I'am a bike mechanic in Phillippines God bless you.

[@Chambers36TheEnter]

No problem, glad it is of some use.

[@thediscoman2001]

cracking little video

[@dirman974]

Thanks for the tip with the hammer 👍

[@wormdamage]

Is there some magic using the hammer method? I hadn't seen this video yet (unfortunately), but had watched one where a guy made it look not that hard with a breaker bar. So a friend and I just removed mine using a 2 foot breaker bar and we barely succeeded. It took both of us, pretty sure I pulled a muscle, and need to re-true my wheel too. And then *now* I run into this video with the mallet and short hex wrench making it look easy.

[@richardkaz2336]

I think you will find is that those two thin shim washers are of two different thicknesses and are used to get the correct chearance for the free hub. So as the ~2.3mm balls wear you can leave the thinnest of the shims out and use the slightly thicker plus the thick washer to get the correct axial slack or play (put which ever washer not used in a place that you will find later like with spare bearings and balls). Depending on the amount of axial slack of the free hub you may leave the slightly thicker shim out and use the very thin and thick washer. Another option is to replace the old balls with new and with wear of around 0.05 - 0.1mm. Most engineering bearing outlets had in stock shim washer and what information they need was th ID, OD and thickness in thousandth on a mm or inch.

[@tonyconnors1342]

Very helpful thank you.

[@stylo78rs30]

Great thank you !

[@budycelyn]

that's a good idea to use the pipe strap to hold the freehub, my method is to drop the block part of the cassette back on and use the chain whip to hold it

[@Chambers36TheEnter]

That makes sense as most people who would end up stripping down a freehub already have those tools rather than a pipe strap.

[@drengskap]

Top tip - the cap off a cheap Bic ballpoint pen makes a very handy little scoop for picking up and positioning little ball bearings.

[@Chambers36TheEnter]

Very nice way of dealing with the problem.

[@datnguyen5463]

I saw on KZbin a mechanic use the magnetic tip of a mini screwdriver to pick up and arrange ball bearing, tried it and still love this method.

[@cosinus_square]

I have the same tub of Comma grease, bought from Halfords at one of their service mechanics recommendation, that's what they use internally for servicing apparently. Had it 4-5 years now, built a dozen bikes and serviced double that, still half a tub left. By now I suspect it just grows back, lol, all while Shimano's neon green grease seemed to just evaporate.

[@Chambers36TheEnter]

I'm in the same situation, no idea how my tub of grease is, it will probably out live me.

[@cosinus_square]

@@Chambers36TheEnter lol, i do appreciate the ease of filling my grease gun though using the hole in the grease cover.

[@Sekhmet6697]

I didn't know about the rubber "monkey wrench" tool, could come in handy when you need to remove the body of a freehub that's not laced to a wheel, so you can have some leverage.

[@Chambers36TheEnter]

Me either until I decided to try and fix mine

[@pistopit7142]

I've ordered 14mm hex key, I prey it will fit since you have used 15mm here.

[@peterbedford2610]

I have an HG shimano free hub that has a stripped hex bolt. Any ideas to unfasten it?

[@Bianchi77]

Nice video, thanks for sharing :) @30:23, what's the tool name, orange color for holding the freehub body?

[@Chambers36TheEnter]

That's a Strap Wrench. 👍 The one I used is a Boa Strap Wrench.

[@jojoparedes3135]

👍

[@user-sk8pd6tv9l]

How to configure a Free body hub with larger teeth, shorter gear. I have a dura ace wh-9100

[@Leo-gt1bx]

Can this be done with QR hubs?

[@makantahi3731]

and what did you repair on no faulty hub

[@3niknicholson]

Thanks for the vid, very informative, I'm just recently learning this stuff, BUT, query: If you can tighten the notched nut enough to seize the bearings, surely that indicates that it needs a bit more shimming. There's no locknut so surely the notched nut should be torqued enough so it doesn't come loose on its thread. I mean, you wouldn't use that method to adjust your cup and cone bearings; there's a locknut used. As I said, I'm still learning, maybe there's something I don't get, correct me if I'm wrong.

[@Chambers36TheEnter]

Hi thanks for the feedback. I believe shimano made these freehubs as throw away goods, for them not really to be serviceable by the public, you basically buy a new one once it goes wrong. I'd guess they, shimano must know the factory torque settings but if you was concerned that it could come undone then locktite is always an option, I'd personally use the blue stuff which is medium strength, you can get purple with is very light or red which is very strong. I just done it by feel, made it too tight and then slowly adjusted it from there.

[@robflohil774]

Those very thin washers inside are meant to remove any play in the bearing {caused by wear}. Just remove one of the thin washers and tighten the cone. If there is still play, remove the 2nd thin washer as well. If the wear is really grave, you might remove the thicker washer. Removing a combination of 1 or 2 or even all 3 washers should do the job in any particular case. Good luck!

[@solarheat9016]

@@Chambers36TheEnter I think that the reason you could get it too tight was because of grease between the washers. If you did not put it there then it oozed in there from the bearing area.

[@LetsDiscoverMauritius]

What is the size of the socket tool to remove the bearing cub?

[@Chambers36TheEnter]

You need a 15mm allen key for the freehub body and then the other tool does not have a size. It's just called "freehub body remover"

[@14TacomaDR]

I am going into the 3rd week waiting for a delivery for a Shimano free hub for my 2020 Specialized Turbo Levo . They say in it shipping but can't say when it will arrive . Summer flying by and I can't ride. The number on mine is fh-mt510-b . Would any of the other models be compatible ?

[@Chambers36TheEnter]

I could not tell you, sorry.

[@maciejs2799]

It's any diference about balls inside??? Upper and down? How many on down and Upside?? Thanks.

[@makantahi3731]

no, same,

[@304HATS]

I have a Deore XT FH-m8000 rear hub and my pawls broke, the connector thing for the pawl to the spring chipped off and I was wondering where I could get replacement pawls for my hub.

[@Chambers36TheEnter]

Probably only from a used Shimano hub, as far as I know they don't offer any spares for them officially.

[@Desi365]

Nice but what sort of lubricant do you put in there ? Regular hub grease or oil or something else ? The problem is you want grease for the bearings but you want oil for the pawls to keep clicking freely.

[@Chambers36TheEnter]

I just went with general purpose grease, Lithium stuff that is NIGL 2 which is it's consistency. It's quite thin as to avoid the pawls sticking. From the factory it just had your regular looking grease and as there's no information from Shimano on the matter it's a go with what you think is best option.

[@ryanstark2350]

There is not much force applied to these bearings because they just come into play when you freewheel. As long as it doesn't dry out.The pawls certainly shouldn't have thick grease on them. You can just use oil in the freehub parts. The wheel bearings on the other hand definitely need thicker grease. In my opinion, most bikes come overgreased. Thick grease in the freehub bearings and too much grease in the wheel bearing cartridges. Cup and cone style bearings are OK with lots of grease because excess will just push out anyway but the cartridges style bearings are best with less grease in my opinion.

[@ryanstark2350]

And if you were racing professionally you would use little and thin lubricant everywhere and remove dust caps and anything which increase drag. Bike manufacturers do the opposite using lots of thick grease because it makes sure of long life without too much maintenance. The best is somewhere inbetween and do maintenance checks now and again. If you get this right you will feel a noticeable performance improvement. Bearing cartridges are also not as good as cup and cones. Shimano still use the old cup and cones method but these need to be checked more often. Most wheels on bikes are quite bad performance nowadays. I just completely overhauled 30 year old cup and cone Shimano hubs and a set of newer cartride Bontrager wheels. The older Shimanos way outperform the newer Bontragers after servicing.

[@shauncaruana9406]

Hi, can you help me here please. This is the size of my freehub 1520-M24R32-03 but i want to upgrade to a better one, but i dont know which one to order online thanks.

[@Chambers36TheEnter]

Hi I think your best option would be to contact Giant directly. It's possible it's a hub that is made by a different company and then Giant put their name on it. Its from a Talon 29" 2020 model, might be better to buy a different wheel and sell your current one.

[@user-mx7cn2fn6q]

نايس

[@Chambers36TheEnter]

على الرحب والسعة

[@fernglez60]

Do u have a part number for the free hub removal tool?

[@Chambers36TheEnter]

Afraid not, it is just a generic tool made cheaply and stuck on places like ebay. There is a TB1018 tool but you'd need to make sure it's the right diameter as I have never used it.

[@namdarbolour9890]

I don't see how you can adjust play of the freehub internal bearings, as you say. The spanner nut just bottoms out, and the play is determined by the factory machining, and you are stuck with that, right? The play on these bearings is not critical because they only roll when freewheeling (they don't roll when pedaling), and further, they don't hold the weight of the bike. If it were possible to adjust these bearings, there would have to be a locknut, which I don't see.

[@Chambers36TheEnter]

Well when tightening the top nut if you over do it then they won't spin at all, if they do they will depending on the hardness of the BB either wear down the freehub body or the softer BB will wear down quickly. If don't do it enough and there's more freeplay in the freehub than there was originally which means the cassette will be rocking back and forth. There's no real adjustment, just finding the right level of tightness.

[@bbrages]

The "thin washers" are shims for setting the clearance in the internal bearings. On mine, one is 0.1 mm and the other is 0.2 mm.

[@3niknicholson]

I made my above comment before I read your's. I think we're both saying the same thing. I found mine to be needing more shims in order to set the ball bearing freeplay/preload correctly with the notched nut tightened to secure torque. I guess I could've achieved the same by very very careful use of the right Loctite on the threads.

[@yunusturel763]

İ need this freehub but cannot find. Can you send link if you know how can i buy ?

[@Chambers36TheEnter]

Look for FH M678 on google. There's many on ebay also. I can't post any links as KZbin blocks them but it's a pretty common freehub.

[@junil6664]

is it possible to just replace the freehub body?

[@Chambers36TheEnter]

Yeah you just buy the fh m678 and bolt it on, saves a lot of time really.

[@cocoboy5215]

can I just replace it with new hub if i dont know how to repack the hub?

[@Chambers36TheEnter]

Yes, undo the old one and screw in the new one.

[@nickh3533]

Much easier to replace. I bought a new freehub for £15 I'm pretty sure it would have taken me hours to mess about with all those fiddly ball bearings, life is too short! But if you're time rich/cash poor or you can't get the parts then being able to service your existing freehub is a necessity!

[@sirnyonyo]

Hey dude, do you know exact dimensions of those 3 washers from inside body? They are from 23:40 Thx

[@Chambers36TheEnter]

No idea I'm afraid. I don't have this hub around to check.

[@ludinaucnik6158]

@@Chambers36TheEnter I cant find that info anywhere. Thx anyway,

[@user-pe2ic5cb2t]

How many balls on top and down 37/34?? Or 36/35 ?

[@Chambers36TheEnter]

I never counted them, I just went on how it looked and fitted. Around 70-80 BB in total for top and bottom.

[@nathandiday9775]

Je compte 36 pour le bas et 34 pour le haut (je vois bien la différence entre les deux car la graisse pour celle du haut est rouge)

[@thedarksideofianmotobikevl2171]

What are the size?

[@GNX157]

28:00 almost every Shimano freehub I see from new has that bearing adjustment too loose, causing the cassette to have play in it.

[@makantahi3731]

yes, i played with spacers but nothing better, because beatings are not parallel

[@LetsDiscoverMauritius]

What is the bearing size inside the hub body?

[@Chambers36TheEnter]

3/32 which is 2.38mm

[@LetsDiscoverMauritius]

@@Chambers36TheEnter no i meant inside the body, which numbered to 25. Not the bearings outside.

[@Chambers36TheEnter]

@@LetsDiscoverMauritius Do you mean at 25:10?

[@LetsDiscoverMauritius]

@@Chambers36TheEnter yes the 25 bearings.

[@Chambers36TheEnter]

@@LetsDiscoverMauritius The bearings for the freehub are all the same size.

[@dariott1542]

Buonasera,le sfere all'interno che diametro sono?

[@Chambers36TheEnter]

3/32 bearings.

[@kurtriedel3208]

You have that hub the part that holds the pawl I think that what it's call them the part that screws into the Hub what is that called. I have a SP-DOC2 HUHASD2FH spin doctor hub you can't get parts they don't sell them you need to buy the whole hub I think that's wrong so if I can find out what that part is maybe I can find a part number thank you

[@Chambers36TheEnter]

I can't really help you sorry. SP-DOC2 seems to be Halo branded and I think it's going to be difficult to get spare parts. Even for shimano freehubs they don't like selling spares, they want you to buy new complete unit. As for names of parts Freehub body Pawls Pawl retaining spring I don't know any other part name, sorry. Good luck.

[@bartomiejo.8303]

Hi there! Guys, I need some help with cylinder Shimano 105 FH 5600. Anybody?

[@Chambers36TheEnter]

This has a diagram of the rear hub hollandbikeshop.com/images/EV-FH-5600-2458C.pdf Part Y-3CJ 98070 The issue with Shimano is if they use the same freehub body on a different hub they will give it a different part number. So potentially your freehub will be on a newer set of wheels where it would be easier to find a replacement part.

[@bartomiejo.8303]

@@Chambers36TheEnter Thanks for quick reply! My issue is that I diassembled almost whole hub. In cylinder (part no. 15) I have one plastick part and one gum. I'm deductink that part no. 16 is metal, to make it kinda waterproof. To be honest, it was fee years back and I'm not sure how put it all together. Is there any chance for contact?

[@pistopit7142]

Also it is way to much tools and work involved . I just bought a new hub for £30.

[@rajeshshilpakar9673]

Steel ball number please

[@Chambers36TheEnter]

Hi, I never counted them, I just went on how it looked and fitted. Around 70-80 BB in total for top and bottom. I had a pack of 100 BB with around 30 to 35 left at the end. If you add too many they won't fit.

[@davidharrison7779]

Together not togever

[@Themheals]

Soft metal is called chinesium